Phil
Phil

Reputation: 3994

What does the symbol "⊇" mean?

In the attached picture there's a symbol I don't understand. To understand additive functional dependency I need to know what the symbol means. Please advice?

alt text

It's the symbol where it says: "Suppose that X Y and that..."

= ?

Thanks!

Upvotes: 5

Views: 11730

Answers (3)

Pauliinaa
Pauliinaa

Reputation: 71

A ⊇ B -> Superset: A has the same elements as B, or more

A ⊃ B -> Proper Superset: A has B's elements and more

for example:

A ⊇ B -> {1, 2, 3} ⊇ {1, 2, 3}

A ⊃ B -> {1, 2, 3, 4} ⊃ {1, 2, 3}

Upvotes: 1

chillysapien
chillysapien

Reputation: 2316

This symbol is used in set theory to say that X is a superset of Y, ie. All elements of Y are contained within X. Note that X could be equal to Y in this meaning. Without the underlining on the symbol Y would be a strict subset of X meaning they cannot be equal

Upvotes: 11

Frédéric Hamidi
Frédéric Hamidi

Reputation: 262979

It means "X is a superset of Y". The subset symbol is the same but flipped horizontally.

Upvotes: 8

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